Continuous method for preparing aromatic carbonate using a heterogeneous catalyst and a reaction apparatus for the same

ABSTRACT

The present invention relates to a continuous method for the preparation of an aromatic carbonate by reacting a dialkyl carbonate and an aromatic hydroxy compound in the presence of a heterogeneous catalyst, and a reaction apparatus for the same. The continuous method comprises the step of reacting dialkyl carbonate and an aromatic hydroxy compound in the presence of the heterogeneous catalyst in a loop-type, catalyst-containing reaction apparatus, wherein a reactor equipped with a filter in which the catalyst is contained is connected with a heat exchanger portion for providing necessary heat during the reaction, reaction solution is circulated between the catalyst-containing portion and heat exchanger via a circulation pump, and by-products can be eliminated via a distillation column connected with the reactor.

BACKGROUND OF THE INVENTION

(a) Field of the Invention

The present invention relates to a method for preparing an aromaticcarbonate and a reaction apparatus for the same, and particularly to acontinuous method for preparing an aromatic carbonate using aheterogeneous catalyst and a reaction apparatus for the same.

(b) Description of the Related Art

Aromatic carbonates are used as starting materials in the preparation ofseveral kinds of isocyanates and aromatic polycarbonates that do not usea very toxic phosgene gas, and they are synthesized mostly by thetransesterfication of dialkyl carbonates and aromatic hydroxy compounds.In this reaction, typical reactants are dimethyl carbonate and phenol.

However, such transesterfication is a reversible reaction and itsequilibrium constant is very small, and consequently the conversion rateafter reaction is very low and the reaction rate is quite slow, and thusit has numerous difficulties in being used in commercial production.

Several attempts have been made to solve such problems, includingattempting to increase the reaction rate by improving the performance ofa reaction catalyst.

U.S. Pat. No. 4,182,726 disclosed a process of using an AlX₃ such asAlCl₃, UX₃, TiX₃, VOX₃, VX₃, ZnX₂, FeX₃, and SnX₃ class reactioncatalysts, wherein X refers to halogen group elements. Also, U.S. Pat.No. 4,045,464 disclosed using Ti class compounds such as titaniumtetraphenate or Lewis acids.

Further, U.S. Pat. No. 4,552,704 disclosed Ti and Sn class reactioncatalysts such as butyltin oxide hydroxide, U.S. Pat. No. 4,554,110disclosed polymeric tin compounds as reaction catalysts, and U.S. Pat.No. 4,609,501 disclosed a reaction catalyst mixing at least one Lewisacid and at least one protic acid.

These prior arts can be said to try to improve the reaction rate by theaction of the reaction catalyst rather than to improve reactivity by thereaction process, in order to increase efficiency in the preparation ofDPC (diphenyl carbonate) from DMC (dimethyl carbonate).

However, all of the catalysts proposed in these patents are homogeneouscatalysts, and thus when they are used they should be mixed withreactants in a certain ratio. Also, even though reaction by-productssuch as methanol, which are generated during reaction, were allowed tobe continuously eliminated from the reaction system, the reaction ratesshown in the examples were not high.

On the other hand, there have been attempts to use heterogeneouscatalysts as reaction catalysts. U.S. Pat. No. 5,354,923 employed astirring reactor using a catalyst in a powdered form having a surfacearea of not less than 20 m²/g, and U.S. Pat. No. 5,565,605 appliedheterogeneous catalysts such as titanoalumino phosphate for reaction.

However, the heterogeneous catalysts prepared hitherto are in a powderedform and they are subject to reaction and separation processes togetherwith the reactants, and thus they cause a problem of being adhered tothe inside walls of pipes and equipment. They are also problematic intheir re-use after separation because they co-exist with reactionproducts having a high boiling point.

Further, there have been attempts to increase efficiency in thepreparation of DPC by designing unique reaction processes along with thedevelopment of reaction catalysts. U.S. Pat. No. 5,210,268 employed amulti-stage distillation column as a reactor, wherein two reactantshaving different boiling points were counter-currently contacted byinjecting the reactant having a high boiling point to the upper portionof the column together with a homogeneous catalyst and by heating andevaporating the reactant having a low boiling point at the bottomportion of the column to synthesize an aromatic carbonate.

Also, U.S. Pat. No. 5,426,207 disclosed a reaction process using threereactors that were connected in series, and U.S. Pat. No. 5,523,451disclosed a process of applying multiple bubble columns that wereconnected in series to a reactor. Also, U.S. Pat. No. 6,057,470disclosed a reaction process using a reaction distillation method.

However, these processes have numerous difficulties in the separation ofcatalysts because they use homogeneous catalysts or catalysts in apowdered form, and they also have difficulties in economic aspectsbecause a certain amount of catalyst must be continuously supplied tothe reaction system in a continuous operation.

SUMMARY OF THE INVENTION

The present invention has been made in consideration of the problems ofthe prior arts as described above, and it is an object of the inventionto provide a continuous method for preparing an aromatic carbonate thatcan solve all of the problems as mentioned above, is suitable forcommercial production, and can be operated at a low cost, and a reactionapparatus for the same.

It is another object of the invention to provide a continuous method forpreparing an aromatic carbonate by reacting a dialkyl carbonate and anaromatic hydroxy compound in the presence of a heterogeneous catalyst,wherein the catalyst and reactants do not adhere to the inside walls ofpipes and equipment because they are not subjected to reaction andseparation processes, and the reaction products having a high boilingpoint and the catalyst do not co-exist, and a reaction apparatus for thesame.

It is a further object of the invention to provide a continuous methodfor preparing an aromatic carbonate with a low cost and that is capableof minimizing catalyst separation processes and costs that might existin the homogeneous catalyst-based processes requiring the continuousinjection of new catalyst to the reactor, by reacting a dialkylcarbonate and an aromatic hydroxy compound using a heterogeneouscatalyst, and a reaction apparatus for the same.

In order to achieve aforementioned objects, the present inventionprovides a continuous method for preparing an aromatic carbonatecomprising the step of reacting a dialkyl carbonate and an aromatichydroxy compound in the presence of a heterogeneous catalyst in aloop-type, catalyst-containing reaction apparatus.

Also, the invention provides a reaction apparatus for the continuouspreparation of an aromatic carbonate, comprising

a) a reactor equipped with a filter, which is located inside thereactor, for preventing the output of a heterogeneous catalyst and onlyoutputting reaction solution;

b) a reaction solution circulation pump that is connected to the side ofthe reactor on which the filter is equipped;

c) a heat exchanger, which is connected between the reaction solutioncirculation pump and the reactor, for raising the temperature of thereaction solution that is supplied from the reaction solutioncirculation pump to a desired reaction temperature and evaporating it;and

d) a distillation column, which is connected to the upper portion of thereactor, for separating the evaporated reactants that are generated inthe reactor and the heat exchanger into high boiling point componentsand low boiling point components and then condensing the high boilingpoint components to withdraw and direct them to the reactor andoutputting the low boiling point components in a gaseous form.

Furthermore, the reaction apparatus may further comprise

e) a heat exchanger for cooling, which is connected to the upper portionof the distillation column, for condensing the low boiling pointcomponents that are supplied from the distillation column in a gaseousform.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view showing the loop-type reaction apparatus ofthe preserit invention.

Reference numeral 1 is a reactor equipped with a filter, 2 is adistillation column, 3 is a heat exchanger for heating, 4 is a reactionsolution circulation pump, 5 is a heat exchanger for cooling, and 6, 7,8, 9, 10, 11, and 12 are pipes.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will be hereafter described in detail.

The present invention relates to a continuous method for preparing anaromatic carbonate using a heterogeneous catalyst and using a dialkylcarbonate and an aromatic hydroxy compound such as phenol as startingmaterials to prepare an aromatic carbonate and a mixture thereof, and areaction apparatus for the same, characterized in that in order toeliminate reaction by-products generated during the reaction, aloop-type circulation reactor equipped with a distillation column andsilica-supported heterogeneous catalysts are used.

The aromatic carbonate prepared by the present invention is used as astarting material in the preparation of several kinds of isocyanates andaromatic polycarbonates that do not use a very toxic phosgene gas, andit is synthesized by the transesterfication of a dialkyl carbonate andan aromatic hydroxy compound. This transesterfication is an equilibriumreaction that can achieve high reactivity by continuously eliminatingby-products with a relatively low boiling point that are generated bythe reaction. The reaction system provided in the present invention is areactor system suitable for continuous elimination of the reactionby-products as described above, and its efficacy was verified by actualreaction experiments that showed reactivity characteristics such asconversion rate, selectivity, etc. to be high. Also, the reactor systemof the present invention is an economical reaction system that lowerscosts and minimizes catalyst separation processes that might exist inthe homogeneous catalyst-based processes requiring the continuousinjection of new catalyst to the reactor, by using a heterogeneouscatalyst as a reaction catalyst.

For these purposes, the present invention uses a catalyst that isprepared by supporting various kinds of transition metal oxides onsilica so as to solve the problems of separation and re-charging of areaction catalyst, and it provides a uniquely designed loop-type,catalyst-containing reaction apparatus so as to maximize the supportedcatalyst. The aromatic carbonate can be efficiently prepared from such areaction apparatus.

The present invention is directed to a process for preparing an aromaticcarbonate from dialkyl carbonates, wherein the dialkyl carbonate can berepresented by the following Chemical Formula 1:

In the above Chemical Formula 1, R is an alkyl group. The alkyl group asused herein refers to a general alkyl group such as methyl, ethyl,propyl, butyl, and cyclohexyl groups.

The dialkyl carbonate is transesterified with an aromatic hydroxycompound represented by ArOH (Ar is an aromatic group) to synthesize analkyl aryl carbonate represented by Chemical Formula 2 or ChemicalFormula 3 as shown below, and an alkyl alcohol is generated as areaction by-product.

In the above Chemical Formula 2 and 3, each Ar is an aromatic grouphaving 5 to 30 carbon atoms.

A typical reaction formula relating to the reaction process designed inthe invention can be represented by the following Reaction Formulae 1 to3:

In the above reaction Formula 1, 2, and 3, R is an alkyl group and Ar isan aromatic group.

The reactions shown in the above are reversible reactions having areaction equilibrium, they can obtain a high reaction conversion rate byextracting the reaction by-products that are generated during thereaction to the outside of the reaction system, and they can increasethe reaction rate by using efficient reaction catalysts.

In the prior preparation of aromatic carbonates, stirring reactors,which mostly use homogeneous catalysts, were used and by-products havinga low boiling point, which are generated during the reaction, wereeliminated using the distillation column installed in the reactors.However, process difficulties have been encountered in the use ofhomogeneous catalysts because the catalytic components adhere to theinside walls of pipes and equipment used in the process, the catalystsused must be separated and eliminated, and the catalysts must becontinuously supplied to the reactor in continuous reaction so it iscostly.

As a different method, instead of the stirring reactors, there has beenan attempt to increase reactivity by installing several reactiondistillation columns capable of performing reaction and separation ofby-products at the same time, but as it used homogeneous orheterogeneous catalysts in a powdered form, problems generated by thecatalysts still exist.

In order to solve the problems generated by the reaction catalysts ofthe prior arts, the present invention preferably uses a catalyst whereone or more transition metal oxides selected from, for example, MoO₃,Ga₂O₃, V₂O₅, PbO, ZrO₂, TiO₂, CdO, Fe₂O₃, CuO, MgO, Y₂O₃, Mn₃NiO, ZnO,Nd₂O₃, Co₂O₃, RuO₂, Nb₂O₅, and Cr₂O₃ are supported on a carrier such assilica having a size of 1 to 20 mm and having the shape of a sphere,cylinder, ring, etc., as a heterogeneous catalyst. The specific surfacearea of the silica is 20 to 500 m²/g and more preferably 100 to 300m²/g, and the porosity is 0.25 to 0.8 cm²/g and more preferably 0.4 to0.75 cm²/g.

However, the silica-supported heterogeneous catalyst as described abovehas a problem of a low reaction activity in comparison with the volumeor weight of the catalyst. Hence, the invention uses a loop-type,specific reaction apparatus so as to solve such problem. An embodimentof this reaction apparatus is illustrated in FIG. 1.

The loop-type, catalyst-containing reaction apparatus used in theinvention is very suitable in the preparation of aromatic carbonatesusing heterogeneous catalysts having a size of approximately 1 to 20 mm,and it is a loop-type reaction apparatus wherein a reactor equipped witha filter in which the catalyst is contained is connected with a heatexchanger portion for providing necessary heat during reaction. Thereaction solution is circulated during the reaction between thecatalyst-containing portion and the heat exchanger by a circulationpump, and by-products can be eliminated through a distillation columnconnected to the reactor.

More particularly, the loop-type, catalyst-containing reaction apparatusof the present invention comprises a reactor in which the catalyst iscontained. Inside of reactor 1, preferably at the bottom portion, is afilter (not shown in the drawing) that does not output the heterogeneouscatalyst but rather it readily outputs the reaction solution only, and acertain amount of the supported heterogeneous catalyst is charged intothe reactor, through the upper portion of the filter. The amount of thecatalyst to be charged is determined by the amount of the aromaticcarbonate to be produced. That is to say, after the amount of thearomatic carbonate prepared during a given time by a certain amount ofthe catalyst is experimentally determined, the amount of theheterogeneous catalyst necessary for the production can be determined.

After a certain amount of catalyst is charged, a calculated amount ofdialkyl carbonate or alkyl aryl carbonate, and an aromatic hydroxycompound, are continuously injected into the reactor separately or inthe form of a mixture via pipe 6 and pipe 7, which are able tocontinuously supply feeds. If the amount of reaction solution in reactor1 is above a certain amount, the reaction solution is circulated betweenreactor 1 and heat exchanger 3 via pipe 8 using circulation pump 4. Aportion of the reaction solution circulated is output to the outside ofthe reaction system via pipe 9 by the control of the level of thereactor. During the circulation of the reaction solution, thetemperature is raised to a desired reaction temperature using heatexchanger 3, which provides evaporation heat to components having acomparatively low boiling point such as alkyl alcohol, which is areaction by-product, thus enabling the reaction by-products to bereadily extracted.

The low boiling point components and the reaction by-products evaporatedby heat exchanger 3 are input into distillation column 2, where activecomponents having a relatively high boiling point are condensed anddrawn into reactor 1.

The alkyl alcohol, which is the reaction by-product, and alkylcarbonates having a relatively low boiling point, are not condensed andthey are input into the heat exchanger 5 via pipe 10 in a gaseous formand condensed by cooling, and then all or part of the condensate isrefluxed into distillation column 2 via pipe 11 or all or a part isdisposed of via pipe 12.

In the continuous preparation method of the present invention, the highboiling point components comprising a desired aromatic carbonate (finalreactant) are disposed of via pipe 9 or they may be disposed of directlyfrom the side of reactor 1 on which the filter is equipped, and thedisposed aromatic carbonate reactants are subjected to conventionalpurification processes such as distillation or crystallization. When thearomatic carbonate is synthesized using the continuous preparationmethod of the invention, operation of the process is very easy and theactivity of the catalyst is maintained for a long time.

The present invention will be described with reference to the followingexamples in more detail. However, the examples are provided solely toillustrate the present invention, and the present invention should notbe limited thereto.

EXAMPLES

Numbers shown in the following examples are calculated according to thefollowing calculation formula: $\begin{matrix}{{{Conversion}\quad{Rate}\quad{of}\quad{Phenol}} = \frac{\begin{matrix}{{{Mole}\quad{of}\quad{the}\quad{MPC}\quad{Produced}} +} \\{{Mole}\quad{of}\quad{the}\quad{DPC}\quad{Produced} \times 2}\end{matrix}}{{Mole}\quad{of}\quad{the}\quad{Phenol}\quad{Charged}}} & \left\lbrack {{Calculation}\quad{Formula}\quad 1} \right\rbrack \\{{{Yield}\quad{of}\quad{MPC}\quad\left( {{wt}.\quad\%} \right)} = \frac{{Weight}\quad{of}\quad{the}\quad{MPC}\quad{Produced}}{{Weight}\quad{of}\quad{the}\quad{Phenol}\quad{Charged}}} & \left\lbrack {{Calculation}\quad{Formula}\quad 2} \right\rbrack \\{{{Yield}\quad{of}\quad{DPC}\quad\left( {{wt}.\quad\%} \right)} = \frac{{Weight}\quad{of}\quad{the}\quad{DPC}\quad{Produced}}{{Weight}\quad{of}\quad{the}\quad{Phenol}\quad{Charged}}} & \left\lbrack {{Calculation}\quad{Formula}\quad 3} \right\rbrack \\{{{Productivity}\quad{of}\quad{Catalyst}} = \frac{\begin{matrix}{{Production}\quad{Amount}\quad{of}\quad{MPC}} \\{\left( {{or}\quad{DPC}}\quad \right)\quad{per}\quad{Hour}\quad\left( {g\text{/}{hr}} \right)}\end{matrix}}{{Weight}\quad{of}\quad{Catalyst}\quad{in}\quad{Reactor}\quad({kg})}} & \left\lbrack {{Calculation}\quad{Formula}\quad 4} \right\rbrack\end{matrix}$

Example 1

Dimethyl carbonate (DMC) was used as a source of dialkyl carbonate, andas an aromatic hydroxy compound, phenol was used. Dimethyl carbonate(DMC) and phenol, which are starting materials, were pre-mixed at amolar ratio of 3:1 and then they were continuously injected into thereactor using a quantitative high pump at a flow rate of 33.3 g/minute.

The reaction temperature was 160° C., the reaction pressure wasmaintained at 4 atmospheres, and the flow rate of the reaction solutioncirculated by the circulation pump was maintained at 6.0 L/minute. Thereaction was continuously carried out under the same conditions for 12hours or longer. The catalyst used was a heterogeneous catalyst oftitania (TiO₂) supported on silica having a diameter of 3 mm, and theamount of the catalyst contained in the reactor was 1200 g.

As a result of the reaction, the yield of methyl phenyl carbonate (MPC)was 21.7 wt. %, and the yield of dimethyl carbonate (DPC) was 0.34 wt.%. The productivity of the catalyst used was 92.6MPC(g)/catalyst(kg).hr.

Examples 2˜7

The same continuous reaction as used in Example 1 above was carried out,except that the reaction conditions were changed as shown in Table 1below. The reaction results are also shown in Table 1. TABLE 1 CategoryEx. 2 Ex. 3 Ex. 4 Ex. 5 Ex. 6 Ex. 7 Reaction Temperature (° C.) 160 170160 170 160 180 Condition Pressure (kg) 4 5 4.5 5.5 4.5 4.5 Molar Ratio3 3 5 5 5 5 Feed Rate (g/min) 11.5 11.5 11.5 11.5 22.4 33.3 ReactionMolar Conversion 18.46 20.59 24.95 26.64 18.82 11.79 Result Rate ofPhenol (%) Yield of MPC (wt. %) 21.08 32.29 39.30 41.98 29.65 18.55Yield of DPC (wt. %) 0.54 0.69 0.72 0.75 0.54 0.36 Total Feed Amount 690690 690 690 1344 1998 (g/h) Feed Amount of 178.2 178.2 119.3 119.3 232.3345.3 Phenol (g/h) Yield of MPC (g/h) 53.2 59.3 48.1 51.3 70.6 65.8Productivity of 44.3 49.4 40.1 42.8 58.9 54.8 Catalyst (MPC g/catalystkg · h)

Example 8

In order to synthesize diphenyl carbonate (DPC) using the reactionsystem shown in FIG. 1, a considerable amount of dimethyl carbonate(DMC) was eliminated from the reaction products prepared from Examples 1to 7 above using a distillation apparatus, and 50 liters of reactantswere obtained with a certain compositional ratio. The compositionalratio of the reactants was an insignificant amount of methanol, 34.44wt. % of dimethyl carbonate (DMC), 13.92 wt. % of methylphenylcarbonate, 51.64 wt. % of phenol, and 0.01 wt. % of diphenyl carbonate(DPC).

The catalyst used in the synthesis of the diphenyl carbonate was aheterogeneous catalyst where titania (TiO₂) was supported on silicahaving a diameter of 3 mm, and the amount of the catalyst contained inmounted on the reactor was 1200 g. The reactants having theabove-mentioned compositional ratio were continuously injected into thereactor, which is designed in the invention, at a constant flow rate of1592 g/hr using a quantitative pump. The reaction temperature wasmaintained at 173 ° C. and the reaction pressure was maintained at 550mbar.

During the continuous reaction, the reaction by-products having acompositional ratio of 0.2 wt. % of methanol, 43.59 wt. % of dimethylcarbonate (DMC), 2.68 wt. % of methylphenyl carbonate (MPC), 53.52 wt. %of phenol, and an insignificant amount of diphenyl carbonate (DPC) andunreacted reactants were discharged at a constant flow rate of 1274 g/hrvia pipe 12, which is located in the upper portion of the reactor. Thereaction products comprising a large quantity of diphenyl carbonate(DPC) were prepared at a constant flow rate of 318 g/hr via pipe 9 whichis located at the bottom of the reactor.

The compositional ratio of the reaction products thus prepared was 1.49wt. % of DMC, 26.52 wt. % of MPC, 30.90 wt. % of phenol and 41.09 wt. %of DPC. The productivity of the catalyst in this reaction was 111 DPCg/catalyst kg.hr.

Example 9

The same reaction system as in Example 1 was used, and reactants havingthe same compositional ratio were continuously injected into the reactorand reacted. In this example, the flow rate of the reactants to beinjected was increased to 2750 g/hr to improve the productivity of thecatalyst.

The reaction temperature was maintained at 165° C., and the reactionpressure was maintained at 550 mbar. During the continuous reaction, thereaction by-products having a compositional ratio of 0.23 wt. % ofmethanol, 47.95 wt. % of dimethyl carbonate (DMC), 1.09 wt. % ofmethylphenyl carbonate (MPC), 50.73 wt. % of phenol, and aninsignificant amount of diphenyl carbonate (DPC) and unreacted reactantswere discharged at a constant flow rate of 2094 g/hr via pipe 12, whichis located in the upper portion of the reactor, and the reactionproducts comprising a large quantity of diphenyl carbonate (DPC) wereprepared at a constant flow rate of 656 g/hr via pipe 9 which is locatedat the bottom of the reactor.

The compositional ratio of the reaction products thus prepared was 2.74wt. % of DMC, 28.65 wt. % of MPC, 40.57 wt. % of phenol, and 28.04 wt. %of DPC. The productivity of the catalyst in this reaction was 142 DPCg/catalyst kg.hr.

The preparation method and the reaction apparatus for the same in theinvention enable an aromatic carbonate to be continuously prepared witha low cost by reacting a dialkyl carbonate and an aromatic hydroxycompound in the presence of a heterogeneous catalyst, wherein thecatalyst and reactants do not cause a problem of being adhered to theinside walls of pipes and equipment because they are not subjected toreaction and separation processes, and reaction products having a highboiling point and the catalyst do not co-exist.

1. A continuous method for the preparation of an aromatic carbonate,comprising the step of reacting a dialkyl carbonate and an aromatichydroxy compound in the presence of a heterogeneous catalyst in aloop-type, catalyst-containing reaction apparatus comprising a) areactor equipped with a filter, which is located inside the reactor, forpreventing the output of a heterogeneous catalyst and only outputtingreaction solution; b) a reaction solution circulation pump that isconnected to the side of the reactor on which the filter is equipped; c)a heat exchanger, which is connected between the reaction solutioncirculation pump and the reactor, for raising the temperature of thereaction solution that is supplied from the reaction solutioncirculation pump to a desired reaction temperature and evaporating it;and d) a distillation column, which is connected to the upper portion ofthe reactor, for separating the evaporated reactants that are generatedin the reactor and the heat exchanger into high boiling point componentsand low boiling point components, and then condensing the high boilingpoint components to withdraw and direct them to the reactor andoutputting the low boiling point components in a gaseous form.
 2. Thecontinuous method for the preparation of the aromatic carbonate of claim1, wherein said heterogeneous catalyst is a supported catalyst wherein atransition metal oxide is supported on a carrier having a size of 1 to20 mm.
 3. The continuous method for the preparation of the aromaticcarbonate of claim 2, wherein said transition metal oxide is selectedfrom the group consisting of MoO₃, Ga₂O₃, V₂O₅, PbO, ZrO₂, TiO₂, CdO,Fe₂O₃, CuO, MgO, Y₂O₃, Mn₃NiO, ZnO, Nd₂O₃, Co₂O₃, RuO₂, Nb₂O₅, Cr₂O₃,and a mixture thereof.
 4. A reaction apparatus for the preparation of anaromatic carbonate, comprising a) a reactor equipped with a filter,which is located inside the reactor, for preventing the output of aheterogeneous catalyst and only outputting reaction solution; b) areaction solution circulation pump that is connected to the side of thereactor on which the filter is equipped; c) a heat exchanger, which isconnected between the reaction solution circulation pump and thereactor, for raising the temperature of the reaction solution that issupplied from the reaction solution circulation pump to a desiredreaction temperature and evaporating it; and d) a distillation column,which is connected to the upper portion of the reactor, for separatingthe evaporated reactants that are generated in the reactor and the heatexchanger into high boiling point components and low boiling pointcomponents and then condensing the high boiling point components towithdraw and direct them to the reactor and outputting the low boilingpoint components in a gaseous form.
 5. The reaction apparatus for thepreparation of the aromatic carbonate of claim 4, further comprising e)a heat exchanger for cooling, which is connected to the upper portion ofthe distillation column, for condensing the low boiling point componentsthat are supplied from the distillation column in a gaseous form.